Mandrel apparatus for power washing machines



April 24, 1962` E. UMBRlcl-rr ETAL 3,030,971

MANDREL APPARATUS FOR POWER WASHING MACHINES Original Filed Dec. 20, 1954 3 Sheets-TSheet 1 INVENTORS f 6km, mi mM ATTORNEYS April 24, 1962 E. uMBRlcHT ETAL 3,030,971

MANDREL APPARATUS FOR POWER WASHING MACHINES Original Filed Dec. 20, 1954 3 Sheets-Sheet 2 ATTORNEY5 April 24,1962 y E. UMBRICHT ETAL 3,030,971 A MANDREL APPARATUS FOR POWER WASHING MACHINES Original Filed Dec. 20, 1954 3 Sheets-Sheet 3 ATTORNEY5 v o E nited States The present invention relates to power washing apparatus adapted `for industrial applications for cleaning various manufactured articles. This invention is described as embodied in a machine lfor washing under high pressure both the outside and inside of metal parts or assemblies and various other articles, and then for draining the washing liquid out of the articles and drying them. The mandrel apparatus of the present invention forcefully flushes out the internal passages and chambers of complex manufactured articles such as automobile engine blocks and machined castings for removing chips and dirt particles.

In many mass-producing type industrial applications involving the fabrication of complicated machine parts and assemblies, it is necessary at one or more points in the production schedule to remove the various soils or other materials which adhere to both outside and inside the articles and accumulate as a result of the previous manufacturing steps, for example, such soils as moulding sand and metal particles, combined with films of the various cutting oils used during machining. The need for eicient automatic apparatus to provide the required cleaning has become increasingly important, for, in modern machinery such as automobiles, the parts are held to closer tolerances and the presence of only slight amounts of soil or contaminating material causes damage by corrosion and scouring after the parts are assembled and run.

For example, in the automobile industry it used to be true that the washing of the various parts was treated, in effect, as merely an incidental step in the assembly of the automobile. But now there have been vast increases in horsepower and engine speed. The castings are much more complex. V and Y blocks are commonly used, including many borings and oil passages, with provision for hydraulic valve lift systems, etc. With such power, speed and complexity, the tolerances are so close and the finishes are so fine that complete, effective washing of the parts prior to assembly has become one of the key steps in the production line. Incomplete washing of just one portion of any one of the multitudes of passages and surfaces in any one of several parts can quickly result in failure on the test line, resulting in expensive overhauling of the engine.

The type of machine described herein as embodying the apparatus of the present invention is well adapted for cleaning machined castings, such as automobile engine blocks and similar articles which must be thoroughly washed on the outside and have internal passages and chambers which must be forcefully flushed out before final assembly.

In the machine described herein, the articles to be washed are supported one behind another along a path and are intermittently advanced along it. The articles pass in succession through a stage where high pressure sprays and streams of washing liquid are directed on them and the articles pass through an internal flushing stage where their various internal passages are directly and forcefully flushed out by mandrels inserted into the articles through larger openings. Jet forming oriiies in the inserted mandrels are precisely aligned with the smaller passages to be washed, and very high pressure jets of cleaning solution from these orices then flush out the passages. Advantageously, intermittent high pressure air blasts mixed with the washing solution enhance the surge effects of the flushing streams. In later stages the articles are drained out and blown dry.

The complete washing operation is enabled to be carried out Ias a precision, high speed, high eiiiciency step in a productoin line.

Among the many other advantages of the machine described is its high production rate and marked reduction in length. The machine herein provides complete external and internal washing in a short path length.

The various aspects, features, and advantages of the present invention will be more fully understood from the following description considered in conjunction with the accompanying drawings, in which:

FIGURE 1 is a top View of an lengine block washing machine. embodying the invention, the blocks enter the machine at the left end at station No. 1 and leave the machine at station No.20 at the right end;

FIGURE 2 is a side view of the machine of FIGURE 1;

FIGURE 3 is a partial top view, on enlarged scale, taken along the line 3-3 in FIGURE 2, looking down, and showing the mandrel mechanism for washing interior portions of the block;

FIGURE 4 is a partial cross sectional view, on enlarged scale, taken generally along the line 4 4 in FIG- URE 3 looking to the right, showing the mandrel iiushing mechanisms for flushing out the internal passages of the engine blocks;

FIGURE 5 is a longitudinal sectional view, taken along the line S-S of FIGURE 3, and showing on further enlarged scale, the operation of the mandrel mechanisms in being inserted into the block for washing certain internal regions and passages in the block;

FIGURE 6 is an enlarged longitudinal sectional View of one of the mandrels shown in FIGURE 5;

FIGURE 6A is a cross sectional view, on enlarged scale, taken along the line 6A-6A of FIGURE 6;

FIGURE 7 is a further enlarged axial sectional view of the spray tip on the end of the mandrel shown in FIGURE 6; and

FIGURE 8 is a cross sectional view of the spray tip taken along the line 3 3 of FIGURE 7 looking to the right.

GENERAL DESCRIPTION Of Machine and Transfer Apparatus Referring generally to the whole machine as shown in FIGURES 1 and 2, the engine blocks 22, indicated in diagramatic forms as dotted rectangles, enter the machine at the left at station No. l. These blocks, for example, may be coming from a production line in which they have received all of the required machining operations and are being sent through the machine to wash oi and thoroughly clean from them the accumulated soils, metal filings, sand, etc., which have accumulated during the previous production steps. The blocks 22 are being washed in preparation for the assembly of the engine which begins along an assembly line stretching from the right end of the machine. In going through the machine, the blocks Z2 pass in sequence through twenty separate stations, indicated as l through 20, in FIGURE l. These stations are uniformly spaced along the length of the machine. Each station may be considered as being equal in length to the length of one of the engine blocks being washed. A small space exists between the adjacent ends of the blocks in successive stations.

In order to move each of the blocks in the machine simultaneously to the next succeeding station, a transfer mecha- `nism actuated by a hydraulic cylinder 214 shown at the lower right in FIGURE 2, is used. The blocks 22 pause at each station for a brief period of time during which they are washed externally or internally, drained, or blown dry, as the case may be, and then are transferred on to the next station, and so forth on through the machine, nally leaving the machine at station 20 clean and dry, in readiness for assembly.

Stations 1 and 2 are outside of the first housing 25 of the machine. As seen in FIGURE 4, the blocks 22 have a generally V or Y configuration, indicated in phantom lines, and in stations 1 and 2 the blocks are received on supporting tracks which engage outer edges of the bottom of the block or so-called pan rail.

In stations 1 and 2 are located (not shown) certain limit switches or control sensing elements which are used to sense the presence of the blocks 22 in these stations and are inter-connected with the electrical and hydraulic control systems of the machine for controlling its operation. The sensing elements operate to restrain the operation of the transfer cylinder 24 whenever blocks 22 have not yet been loaded into stations 1 and 2, as may occasionally happen when there are delays in the production line ahead of the machine.

Stations 3 through 7 are inside of the housing 25 and comprise a washing stage, generally indicated at 36, for washing the outside of the blocks 22. Considerable internal washing also occurs, of course, but the high speed Washing jets of iiuid are directed mainly at the outside of the machine in this stage 36.

In stations 8 and 9 the blocks are passing through a connecting tunnel in a tunnel housing 46 (seen best in FIGURE 1) between the washing stage and an internal flushing stage 38 which includes stations 10 through 13.

Following the stage 38 is a drain-off stage 50 including two other stations 14 and 15, which are used to drain off the washing solutions which tend, in modern engine blocks with their complicated internal configurations and inter-connecting passages, to be trapped in puddles internally of the block.

Next is the drying stage, indicated generally at 52, including stations 16, 17, 18 and 19 in which the blocks 22 are thoroughly dried by means of high pressure blasts of hot air from a blower 54 driven by a,.motor 56 mounted on top of the housing. The air is drawn by the blower in through a suitable heating radiator 58 and is conducted to positions closely adjacent the block by means of large ducts and manifolds, then being directed by nozzles at desired areas of the blocks.

The streams of hot air are precisely directed at desired predetermined areas of the blocks at each of the stations 16, 17, 18, and 19, and are directed at different angles in the different stations each as is best calculated to obtain the optimum drying effect of the particular parts of the block being dried in that station. The result is a highly etiicient positioned drying operation.

As the blocks pass out of the machine from station 19 through station 20, they actuate other limit and control switches, which are arranged to prevent the machine from advancing the blocks in it until the block at station 20 has been removed from the machine and passed on to the assembly line.

By the use of the controls at stations l, 2, and 20, the machine, in effect, automatically gauges itself to the speed of operation of the production line ahead of it and to the assembly line following it so that the machine always operates eciently at full capacity and yet does not pile up excess blocks into the assembly line. The machine as described herein is capable of thoroughly Washing and drying in the neighborhood of 140 to 160 blocks per hour, both inside and out, with each block as it passes through the machine receiving a number of precisely controlled positioned washing operations and positioned drying operations.

For advancing the blocks from station to station, a transfer mechanism is used, mentioned above, and including a transfer bar 64 extending the full length of the machine. The hydraulic transfer cylinder 24 reciprocates a piston rod 82 connected to a gusset 34 welded to the main transfer bar 64, so as to drive the transfer bar longitudinally in the machine a distance slightly greater than the spacing between the front end of one station and the front end of the next succeeding station.

In order to engage the rear of the pan rail of the blocks 22 and advance them to the right, a plurality of drive pivoted dogs 86 are supported on the main transfer bar 64.

The transfer bar 64 is supported between a pair of tracks 926 formed by spaced parallel channels having their flanges aligned and faced toward each other. Flanged tapered wheels 94 project into the open face of the channels 926 and engage the upper surface of the lower ange of the channel. As shown in FIGURE 4, these lianged wheels 94 are supported by stub shafts projecting into the sleeve portions of lianged sleeves 88 having their flanges welded to the outer faces of the members S0.

Mandrel Flushing Stage After passing through the tunnel stations 8 and 9, the blocks enter the mandrel liushing stage 38, which includes stations lO through 13. In station 10, the block may receive further washing, if desired, in readiness for the first mandrel flushing operation which occurs in station 11. Then in station 12, as seen in FIGURE 3, the block is again washed ofi on the outside by a plurality of pipes 168 and spray nozzles. In station 13 a second mandrel flushing operation occurs, as described in detail below. Stations 1l and 13 are each considered to include both the position of the block when it sits upright on the tracks 26h, as seen in FIGURE 4, and its alternate position shown dotted when it has been inverted.

As shown in FIGURES 3 and 4 in order to lift the Y-blocks from the tracks 2Gb at stations 11 and 13 to swing them up and over into an upside down position, as shown dotted, a pair of fixtures 170 engage the block. Each of these fixtures includes a front and a back generally Cshaped frame 172 and 174, respectively, secured to a rotatable shaft 176 and with inner and outer areas 178 and 180, respectively, to lift the black. A plurality of guiding and supporting rails 182-187 inter-connect the frames 172 and 174 and define a cradle for receiving and holding the wider top half of the block. The rails 184 and 185 support the block when it is inverted. To turn the shaft 176 through 180 .and back, a hydraulic torque motor 188 is directly coupled to the front end of the shaft 176 near the tunnel housing 46. This motor is controlled for smooth acceleration and deceleration.

The manifold frames 30b form watertight ducts and are used to convey washing solution. They are connected by short hollow rectangular supports 190 to a main 192 supplied by a pump 194 driven by a motor 196. The spray pipes 168 in station 12 are supplied directly from the manifolds 30h. Also, as seen in FIG- URES 3 and 4, the left frame 30b is braced against the housing wall 48 by a plurality of transverse beams 197 and 198 with their opposite ends secured to a horizontal wall bracket 200. The transverse braces 197 and 198 serve as supports for the bearings 202 for the shaft 176.

In order thoroughly to flush out the many intricate passages in the block 22 when it is in inverted position, a pair of mandrels 204 and 206 are inserted axially into the block through the opening 205 for the cam shaft and the opening 207 for the crank shaft, respectively. These mandrels are hollow and have a number of radial orifices which become aligned, when fully inserted, with the open ends of the various passages in the block. High pressure streams from these orifices then flush out the passages in the block, as described in detail further below. These mandrels are carried on a trolley 208 supported by pairs of wheels 210 and 212 which roll on a pair of spaced parallel round rods 214 and 215. The left wheels 210 in each pair have generally V-shaped flanges to guide the trolley 208 accurately along the rods 214, and the trolley is prevented from leaving the rods by L-shaped retainers 216 extending out under the rods. As seen in FIGURES 4 and 5, the front ends of the rods 214 and 215 are secured to the end wall of the housing 48 above a transverse stiffener 217, and their rear ends are fastened to cross pieces 218 supported by vertical struts 220 from one of the main cross braces 198. Supported on top of the main cross beams 198 are horizontal stop plates 222 (FIGURE 5) which abut against the blocks 22 in their inverted position so as to position them precisely ahead of the mandrels 204 and 206. An additional vertical stop 224 engages the front end of the block to prevent any chance for the block to shift ahead in the fixture as the mandrel is inserted.

In order to drive the trolley 208 from its initial position shown in full lines in FIGURE 5 ahead to the dotted line position with both mandrels fully inserted into the blocks and then back to the initial position, a hydraulic Vcylinder 226 (FIGURE 1) is used with its piston rod vthe crank shaft bearing holes 207 are larger, and it projects frorn la similar but higher box 234 at the right end of the tro-lley.

These boxes 232 and 234 are connected by flexible hoses 236 and 238, respectively, to a suitable high pressure source of washing solution. These hoses 236 and 238 may, for example, be connected directly to the high pressure manifolds 30b. Alternatively, we prefer to supply the mandrels with washing solution under even higher pressure than is available from the manifolds 30b. Thus, the hoses 236 and 238 `are connected to a separate higher pressure supply. For example, the pump 194 may be a two-stage centrifugal pump of the type disclosed and claimed by Emil Umbricht in copending application Serial No. 462,661, filed October 18, 1954, now issued as Patent No. 2,873,685. With this two-stage pump, the

' first stage is connected to the main 192 for feeding the mandrel has an inner coaxial pipe 244 with its rear end connected to the air hose 242 Iand lwith its other end closed off. The mandrel 206 and pipe 244 are held in concentric relation by three radial struts 246. The pipe 244 has a plurality of small radial orifices 248 which are aligned with the larger radial orifices 250 in the mandrel 206. After the mandrel 206 has ben fully inserted for a period of time, a blast of air is shot out through the orifices 248. This air blast has Ia number of effects. In-

itially it accelerates the slugs of washing solution which are leaving the orifices 250 as it is turned on. Then the air blast displaces in considerable measure the washing solution from its path; so that the jets issuing from the orifices 250 act like jets of compressed air with quantities of spray and slugs of solution mixed in. As soon as the air blast stops, the washing solution again surges out of the orifices 250 in effect as solid slugs. The result of this air blast sequence is a highly effective surging, shocking action which dislodges the most stubbornly wedged metal filings or other foreign material from the passages in the block. A series of air blasts can be used, if desired, but Iwe find that a single short blast during the middle of the flushing period when mandrels Iare fully inserted is sufficient. Atiming device, not shown, intervconnected with the electrical `-and hydraulic control circuits actuates a valve to release the air blast through both of the hoses 240 and 242. The cam shaft mandrel operates similarly to the crank shaft mandrel.

In order to flush out the cam sha-ft and crank shaft bearing holes 205 `and 207 as the ends of the mandrels 204 and 206 are inserted to make certain that no dirt particles can jam against the inserted mandrels, a conical wall of spray is generated ahead of the end of the mandrel by a conical deiiector 252 supported by three radial vanes 254 opposite a 'large orifice 256 in the end of the mandrel.

For maximum efficiency it is desirable to have washing solution lfed to the mandrels 204 and 206 only while the blocks are fully inverted, i.e., only during the Iadvance and return of the trolley 208. =For this pur-pose, as shown in FIGURE 3, the hoses 236 and 238 are connected through a two-way valve 258 having an actuating arm shown in FIGURE 4 at 260 lwhich is oammed over by Va trigger 262 on the hub of the frame 172 of the cam shaft mandrel flushing fixture in station 11. This two-way valve 258 is preferably supplied from `a higher pressure source such as the second stage of a two-stage pump las described above. When the valve arm 260 is actuated, this high pressure source is connected to the hoses 236 and 238, but otherwise it is connected into the manifolds 301) so as to boost their pressure.

The fixture is described as adapted for engaging the enlarged top portion of V or Y-block engines, yand this is a preferred arrangement whereby the track 26b is advantageously enabled to 'be continuous through the mandrel stage 38 and likewise the transfer mechanism advantageously is enabled to be continuous throughout this stage. However, the fixture 170 can be arranged similarly to engage blocks 22 which are sent through the machine upside down, as may be desirable in certain production lines. In this case, the arms 178 and 180 and the supporting rails 182 `and 187 are arranged to engage the inclined faces of the block at the top end of each cylinder. That is, with the 'blocks inverted, rails 182 `and 187 engage the faces corresponding to those now engaged by the rails 184 and 185.

For straight in-line engines, the depending arms 178 and 180 can be `arranged to project down on either side and underneath the edges of the pan rail of the machine, or short portions of the track 26b in stations 11 and 13 are detached from the rest of the track and are connected to the frames 172 and 174 and are used to lift the blocks when they `are inverted.

Among the yadvantages of this flushing operation by the two mandrels in sequence is that many of the passages in the block are inter-connected between the cam shaft and crank shaft bearing holes 205 and 207. Thus, these passages purged yare first in one direction and later in the other by the surging cleaning action of the cleaning solution `and air from the mandrels 204 and 206.

Although these mandrels are described as both inserted from the same respective ends of the blocks or other articles to be flushed they can in certain cases depending upon the configuration of the blocks or other articles be inserted into the opposite sides of the blocks or other articles either simultaneously or in sequence. Moreover, these mandrels can be inserted into the blocks or other articles from various angles or positions either from above, below, or either side in accordance with the configuration of the items being flushed. This application is a division of application Serial No. 476,138, filed December 20, 1954, and now issued as Patent No. 2,918,071.

From the foregoing description it will be understood that the various power washing mandrel and apparatus of the present invention are well adapted to provide the many advantages discussed above, and that they can be adapted to a wide variety of industrial washing and cleansing operations and that various changes or modifications may be made therein, each as may be best suited to a particular application, and that the scope of the present invention as defined by the following claims, is intended to include such modifications or adaptations limited only by the prior art.

What is claimed is:

1. In power washing apparatus of the type adapted for fiushing out the internal cavities of articles, mandrel means adapted to be inserted into the cavities in said articles for flushing them out, comprising a substantially cylindrical outer tube supported from one end and having its opposite end free, an orifice in the free end of said tube, a spray head associated with said orifice and adapted to generate a substantially continuous conical wall of spray in an annular pattern surrounding and preceding the end of Said tube, said tube having a plurality of openings in its side, and an inner tube within said cylindrical tube and defining a space therebetween, said inner tube having a plurality of openings in its side aligned with respective ones of said orifices in the side of said outer tube.

2. In article washing apparatus, mandrel means as claimed in claim l and including a connection from a source of fiushing liquid to said space between said inner and outer tubes, and a connection from a source of high pressure oaseous material to the interior of said inner tube.

3. In a power washing machine for automatically cleaning automobile engine blocks and similar mass-produced engine blocks, mandrel apparatus for insertion into the crankshaft and cam shaft bearing openings for removing from the interior passages and `openings of the blocks dirt particles and other materials which have accumulated as a result of previous manufacturing steps comprising a first hollow elongated mandrel and a second hollow elongated mandrel, a source of cleaning liuid under pressure, fluid conducting means connecting said source with the interiors of said hollow mandrels for supplying the cleaning fluid thereto, first reciprocating support mechanism secured to the back end of said first mandrel for inserting the free end thereof longitudinally into the crankshaft bearing opening of' an engine block and for withdrawing it therefrom, the wall of said first mandrel having a plurality of openings formed therein for directing the cleaning fiuid laterally from said first mandrel for cleaning out the interior passages and openings in the block communicating with the crankshaft bearing opening, second reciprocating support mechanism secured to the back end of said second hollow mandrel for inserting the free end thereof longitudinally into the cam shaft bearing opening of an engine block and for withdrawing it therefrom, the wall of said second mandrel having a plurality of openings formed therein for directing the cleaning fluid laterally from said second mandrel for cleaning out the interior passages and openings in the block communicating with the cam Shaft bearing openmg.

4. In a power washing machine for washing manufactured articles having passages therein with smaller lateral passageways intersecting with said passages, a flush out and washing mandrel mechanism comprising an outer hollow cylindrical wall defining a tubular member, a reciprocating support mechanism secured to the back end of said tubular member, said cylindrical wall having a plurality of orifices therethrough positioned at spaced points along the length of said tubular member, a pipe extending axially through said tubular member having a plurality of orifices therein each aligned with one of the orifices in said tubular member, a source of gas under pressure connected to said pipe, a source of washing liquid connected to the annular space within said tubular member surrounding said pipe, a nozzle on the front end of said tubular member having a large axial orifice therein, a conical defiector positioned in front of said axial orifice with the conical surface thereof facing said OU'CS, and a narrow radial vane securing said conical deiiector in position, whereby said mandrel generates a conical wall of spray in front of it as the mandrel is inserted into cavities within manufactured articles.

5 In a power washing machine for washing automobile engine blocks and similar complex manufactured articles mandrel flushing apparatus for washing out the articles and for dislodging chips and dirt particles from the interior passages such as crankshaft and cam shaft bearing openings and interior oil passages communicating therewith comprising a first hollow elongated mandrel, a reciprocating support mechanism secured to the back end of said mandrel for moving said mandrel longitudinally along its axis, guide means for guiding said reciprocating support for inserting the free end of the first mandrel into a crankshaft opening and for withdrawing the mandrel therefrom, a second hollow elongated mandrel offset from said first mandrel, said reciprocating support mechanism being secured to the back end of said second mandrel for inserting the free end of thev second mandrel into a cam shaft opening at the same time as said first mandrel is inserted into a crankshaft opening and for withdrawing the second mandrel therefrom, a source of washing fluid under pressure, means connecting said source with the interiors of said hollow mandrels, the walls of said mandrels having a plurality of orifices therein for projecting jets of the washing liquid laterally from said mandrels for washing out the articles and for dislodging chips and dirt particles from the interior oil passages communicating with the crankshaft and cam shaft bearing openings.

6. In a power washing machine for automatically washing automobile engine blocks and similar types of mass-produced engine blocks and the like, mandrel flushing apparatus for dislodging chips and soil materials resulting from previous manufacturing steps from the interior cavities and passages in the block, such as the crankshaft and cam shaft bearing openings and oil passages communicating therewith comprising a hollow elongated mandrel having a plurality of lateral orifices extending through its wall, a movable support carriage for said mandrel, said mandrel being secured near its back end to said carriage with the front end of said mandrel being directed toward one of said bearing openings and with the mandrel longitudinally aligned with said bearing opening for insertion therein, guide means for said movable support carriage for guiding the mandrel into said bearing opening, drive mechanism for advancing and withdrawing said carriage along said guide means for inserting said mandrel into said bearing opening and for subsequently withdrawing the mandrel therefrom, a source of washing liquid under pressure, liquid conducting means connecting said source with tbe interior of said hollow mandrel for supplying the liquid thereto, said liquid issuing through said orifices for dislodging chips and soil materials from the interior cavities and passages in the block, and valve means for surging the washing liquid out through said orifices for providing a surging, shocking action in the liquid issuing through said orifices.

7. In a power washing machine for washing automobile engine blocks and similar complex manufactured parts, mandrel fiushing apparatus for automatically washing and flushing out the crankshaft and cam shaft bearing openings and the interior cavities and oil passages communicating with the bearing openings comprising a first and a second hollow elongated mandrel, movable support means, said elongated mandrels being connected at their back ends to said movable support means, guide mechanism for said movable support means for guiding said first mandrel longitudinally into the crankshaft bearing opening of an engine block while simultaneously guiding said second mandrel into the cam shaft bearing opening of an engine block, drive mechanism for moving said support means toward and away from an engine block for simultaneously advancing said first and second mandrels into the crankshaft and cam shaft bearing openings respectively and for withdrawing said mandrels therefrom, a

9 Source of washing uid under pressure, and fluid conducting means for connecting said source to the interiors of said hollow mandrels, the walls of said mandrels having a plurality of orifices therein for projecting jets of the washing fluid laterally from said mandrels for flushing out the interior cavities and oil passages.

8. In a power washing machine for washing automobile engine blocks and similar complex manufactured parts, mandrel ushing apparatus as claimed in claim 7 and wherein said first mandrel which is adapted for insertion into the crankshaft bearing openings is larger in diameter than said second mandrel which is adapted for insertion into the cam shaft bearing openings.

9. In a power washing machine for automatically washing automobile engine blocks and similar types of mass-produced engine blocks and the like, mandrel flushing apparatus for dislodging chips and dirt particles from the interior cavities and passages such as the crankshaft and cam shaft bearing openings and oil passages cornmunicating therewith comprising a hollow elongated mandrel having a wall with a plurality of orifices extending through said wall, a movable support carriage for said mandrel, said mandrel being connected near its back end to said carriage with the free end of said mandrel being aligned with a said bearing opening, guide means for said carriage for guiding the free end of said mandrel into 10 said bearing opening, drive mechanism for advancing and withdrawing said carriage along said guide means for inserting said mandrel and for subsequently retracting the mandrel therefrom, a source of washing fluid under pressure, fluid conducting means for connecting said source with the interior of said hollow mandrel; and control means for surging said washing uid when said mandrel is inserted into the engine block.

10. In a power washing machine for automatic washing as claimed in claim 9, mandrel flushing apparatus wherein said guide means comprise parallel round rods and said movable support carriage for said mandrel includes a plurality of wheels with V-shaped flanges rolling on said rails for accurately guiding the carriage to insert said mandrel without striking the block itself.

References Cited in the le of this patent UNITED STATES PATENTS 2,187,324 Many Ian. 16, 1940 2,418,766 Green Apr. 8, 1947 2,492,216 Green Dec. 27, 1949 2,563,130 Mylchreest Aug. 7, 1951 FOREIGN PATENTS 662,908 Great Britain Dec. 12, 1951 

